Researchers at Toxin Alert Inc. in Mississauga, Ontario, Canada, have developed a plastic wrap that they hope will detect dangerous levels of bacteria in food. The product, which will be 15 to 25 percent more expensive than regular wrap, uses chromophore-labeled detector ligands to capture and accumulate pathogens in a nutrient gel, where they grow in distinctive and visible patterns.

Critics suggest that the wrap, which is designed to detect E. coli, Salmonella and Listeria, lacks the sensitivity to detect low levels of the pathogens. The company acknowledged that the wrap was designed to monitor gross contamination. Different ligands could detect pesticides or genetically altered food.